You would have simultaneous buy & sell open orders on the same option contract. That's not allowed. Not an IBKR limitation, but a limitation of US option markets where only market makers can have simultaneous buy & sell orders open on the same option contract.

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Since both your orders are at same entry price, you can just have 1 open order for the total qty, and then have 2 different close orders, each with its qty, profit & stop loss targets, and then just link them together in an OCA group so you get the overfill protection.